| 
                     
                        | (84) | Designated Contracting States: |  
                        |  | AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO
                           PL PT RO SE SI SK SM TR |  
 
                     
                        | (71) | Applicant: ABB Research Ltd. |  
                        |  | 8050 Zürich (CH) |  
 | 
                     
                        | (72) | Inventors: |  
                        |  | 
                              BERGGREN, BertilS-724 76 Västerås (SE)
MAJUMDER, RajatS-723 44 Västerås (SE)
RAY, SwaksharS-723 44 Västerås (SE)
CHAUDHURI, BalarkoLondon W12OTR (GB)
RAY CHAUDHURI, NilanjanLondon SW10 9QW (GB)
 |  
 
                     
                        | (74) | Representative: Savela, Reino Aleksi |  
                        |  | ABB AB 
                           Intellectual Property 
                           Ingenjör Bååths Gata 11 721 83 Västerås
 721 83 Västerås (SE)
 |  
 |